I think this because, thematically, Bruce goes through a different arc to the Gotham characters and city, despite Bane saying he will torture them both in the same way: their soul, via false hope.

Bane feeds Bruce hope by putting him in an open prison, that he is allowed to attempt to escape. He feeds Gotham hope by seizing it away from the corrupt, and returning it to the people. Bruce loses his hope because he cannot make a jump that a child could. Gotham loses hope because.......

Nothing visibly happened other than people stayed indoors, however, given Joker was likely a part of the formation of the Dent Act, he would have been freed, perhaps to deliver Gordon's speech, and have a reign of terror that removes Gotham's hope, perhaps it would be Joker that Robin stands up to, rather than Chris Judge. Then Joker, Batman and Robin could have had a scene together, where Joker gets to say his hello's and goodbyes. Batman shouldn't have a final soiree without Joker.